An opencut running tunnel of Shenzhen Metro passes through underneath an area with dense highrise buildings. The job site of the tunnel is narrow, the surrounding ground of the tunnel consists of soft materials on the top and hard materials at the bottom and there exist various underground obstacles within the job site, therefore there exit great difficulties in the construction of the retaining structures.This paper introduces the selection and optimization of the construction schemes of the retaining structures, as well as the major construction technologies of retaining structures.